How to care for a bonsai tree

A guide to the pruning and care of a bonsai tree, including different shaping techniques.

By John Casteele
Bonsai trees have been growing in popularity ever since the 80's, when they were featured in one of the "Karate Kid" movies. Add to that the recent trend for Japanese and Oriental decorations in the home, and the bonsai seems like it's here to stay for a while.

A bonsai tree maintains it dwarf stature by the rigorous pruning of both its roots and its branches. The design of the tree depends both upon the tree itself and the one pruning it... even the pot is considered to be a part of the design, and is specially chosen to compliment the tree.

The first part of caring for and shaping a bonsai tree is to get the tree itself. Bonsai trees can be purchased from specialist nurseries, or can be made by training naturally-dwarfed trees found in the wild. The main difference between the two is that nursery trees come pre-shaped and only require regular watering and the occasional repotting, whereas wild trees must be shaped and pruned so as to train them to their shape. Seedlings are best to grow a bonsai from, but require that you shape and prune it from the very start.

A variety of different trees can be used to create a bonsai... conifers such as pines, junipers, and spruces work well, as do deciduous trees such as maples, elms, and birches. When trying to choose your tree, however, keep in mind that a conifer will have full-sized needles while a deciduous tree will form leaves that are proportional to the size of the trunk. Any bonsai will grow larger if left alone, though... after all, it's artificially stunted instead of genetically. (This also means that any seeds produced by a bonsai tree are fully capable of growing full-sized trees.)

To prune your bonsai tree, begin by determining the front and the most natural configuration for training. Remove diseased or broken branches, as well as any branches that cross others, interfere with the design of the training, or that come from nearer to the bottom of the tree. You should leave only a single branch coming from the trunk; the smaller branches that come from this one will be the ones that you train for your bonsai.

You should continue to prune the tree every winter, removing all twigs that interfere with the overall shape of the tree and controlling any new growth. Make sure that any large pruning scars are covered with a protective paint, and hollow out each scar so that it doesn't project from the tree. Work with the branches and twigs that you prune so as to make shaping the tree easier.

When it comes to the actual shaping of the tree, use copper wire to hold the tree into its shape until it begins growing in that manner. The thickness of the wire that you use will depend upon how much the tree resists bending; be gentle with it, as you don't want to snap the branch, but make sure that the wire is as tight as you can get it. Wire conifers in the winter, leaving the wires on for about a year or so before removing them. Deciduous trees should be wired in the summer, and the wires should be removed in the fall of the same year. If you remove the wires and the tree still resists its shape somewhat, don't hesitate to wire it again next year.

When caring for a bonsai tree, keep in mind that it needs to be kept outside most of the time. You can bring it in for short periods, but as it is a natural plant, it needs the air and sun that it finds in nature. Repot the tree every two or three years, using a pot of around the same size. Trim the lower roots back by about half, and use new soil. Water it regularly during the summer (about once a day), but cut back during the winter to once every two weeks.

Caring for the tree can be a big responsibility... you should make pruning it a part of your daily routine and make sure that it has plenty of nourishment. If properly cared for, though, a bonsai can outlive a wild tree... which means that it might outlive you as well.